Vehicle composite test apparatuses are conventionally known wherein, using tires of a vehicle as means to be detected, in addition to basic test items such as the braking, and speed, various positional displacements of wheels such as the toe, camber, caster, and king pin angles that improve the maneuvering stability of the vehicle as well as various test items such as the measurement of light distribution of head lights, and tail lights that will be carried out on the basis of the vehicle center line between the tires can be measured at tire setting positions provided on support bases.
In this type of test apparatus, a rear wheel measuring section A and a front wheel measuring section B that are constituted independently as shown in FIG. 4 are arranged to correspond to the wheel bases of a vehicle, the front wheels and the rear wheels are placed respectively on support bases 53, 53' positioned on the right and left sides of the measuring sections A, B, and thereby the various tests mentioned above are carried out.
The constitution of the measuring sections A, B is such that a pair of rails 52, 52' are placed on rectangular fixed bases 51 extending in the direction of the width of the vehicle, and are arranged in parallel along the direction (hereinafter referred to as the direction of the width of the vehicle) orthogonally to the measurement reference line Ls corresponding to the central line extending along the direction of travel of the vehicle, the pairs of support bases 53, 53' are arranged on the opposite sides of the measurement reference line Ls, positioning means 56 for positioning wheels 10 with the opposite sides of the wheels 10 clamped by a plurality of rollers 54, 55 provided on the support bases 53, 53' are swingably supported on the support bases 53, 53' through support shafts, and said pairs of support bases 53, 53' are connected movably toward or away from one another by link-like connecting mechanisms, called "equalizers", 58 having fixed rotation supporting points C, C' on the measurement reference line Ls.
The wheels on the side of the front wheels 10A and on the side of the rear wheels 10B are positioned on the support bases 53, 53' by the positioning means 56. Then following the positioning operation, the connecting mechanisms 58 move the pairs of support bases 53, 53' symmetrically toward or away from the fixed rotation supporting points C, C' thereby aligning the measurement reference line Ls connecting the fixed rotation supporting points C, C' with the vehicle center line Lc. Due to this alignment the above-mentioned various test items that are tested with the wheels 10 of the vehicle being means to be detected can be tested accurately.
However, in such apparatus, since the line C-C' connecting the fixed rotation supporting points and the rails 52, 52 are integrally attached respectively on the fixed bases 50, 51 on the side of the front wheels 10A and on the side of the rear wheels 10B, the direction of movement of the pairs of support bases 53, 53' movably attached to the rails is restricted.
On the other hand, vehicles include, for example, attaching position errors of front wheels 10A and rear wheels 10B due to various production conditions, and cannot be produced with the attaching positions of wheels of the vehicles being very precise. Therefore, if the wheels of a vehicle having attachment position errors are clamped forcibly on the support bases 53, 53' whose positions are restricted approximately to the shape of the letter H by the rails 52, 52' and the line C-C' connecting the rotation supporting points, the vehicle center line Lc and the measurement reference line Ls may come out of alignment in some cases, and accurate measurement becomes impossible.
Further, in the above prior technique, to place tires in the prescribed central positions of the support bases 53, 53', it is necessary that the intervals between the support bases 53, 53' on the side of the front wheels 10A and on the side of the rear wheels 10B are moved by equalizers toward or away from one another to correspond to the width of the vehicles to be tested. The widths of vehicles are not necessarily uniform due to scattering during production even if the vehicles are of the same type, and in practice it is quite difficult to move the support bases 53, 53' toward or away from one another to correspond to the intervals between the wheels of the individual vehicles to be tested.
Further if the vehicle is placed on the support bases 53, 53' with the vehicle dislocated to one side, or is introduced obliquely by mistake, if the wheels are clamped forcibly even by the positioning means 56, the vehicle center line Lc and the measurement reference line Ls are out of alignment in some cases, and therefore accurate measurement becomes impossible.